The invention is directed to video image capture and processing systems and methods therefor.
There are many methods for recognizing or identifying an individual on a transactional basis. These include analyzing a signature, obtaining and analyzing an image of a fingerprint, and imaging and analyzing the retinal vascular patterns of a human eye. All of these recognition techniques have a common drawback, they require the individuals being recognized to perform some positive act, either signing their names, placing one of their fingers on an imaging plate or positioning themselves using a head-rest or bite bar or position their eye relative to an eyepiece so that an image of their vascular patterns may be captured.
Recently iris capture and analysis has been gaining favor as a method for identifying individuals. This technique is described in U.S. Pat. Nos. 4,641,349 to Flom et al. and 5,291,560 to Daugman and in an article by J. G. Daugman entitled xe2x80x9cHigh Confidence Visual Recognition of Persons by a Test of Statistical Independence,xe2x80x9d IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 15, no. 11, pp. 1148-61, November 1993. The systems described in these references require the person being identified to hold at least one of their eyes in a fixed position with respect to an imaging imager while their iris is being imaged. While this procedure may be satisfactory for some applications, it is not satisfactory for quick transactional activities such as using an automatic teller machine (ATM). A person using an ATM typically does not want to spend any more time than is necessary to complete his or her transactions. Consequently, it would be considered an undue burden to ask ATM users to perform any positive act other inserting their ATM card and keying in their desired transactions on a keypad.
This need makes clear that there exists a more general problem of identifying objects or individuals in a passive way that is both fast and accurate.
The invention is embodied in a system which obtains and analyzes images of at least one object in a scene comprising a wide field of view (WFOV) imager which is used to capture an image of the scene and to locate the object and a narrow field of view (NFOV) imager which is responsive to the location information provided by the WFOV imager and which is used to capture an image of the object, the image of the object having a higher resolution than the image captured by the WFOV imager.
The invention is embodied in a fully automatic system that obtains and analyzes images of the irises of eyes of a human or animal in an image with little or no active involvement by the human or animal. According to one aspect of the invention, the system includes both WFOV and NFOV imagers. The system includes control circuitry which obtains an image from the WFOV imager to determine the location of the eyes and then uses the NFOV imager to obtain a high-quality image of one or both of the irises.
The invention is also a method for obtaining and analyzing images of at least one object in a scene comprising capturing a wide field of view image of the object to locate the object in the scene; and then using a narrow field of view imager responsive to the location information provided in the capturing step to obtain higher resolution image of the object.